Robert
Some time ago our coal group were using a digital camera and image analysis
software to do maceral studies - essentially the same approach as a modal
analysis. They were quite successful and were able to carryout large
"production runs" of coal samples, even though colour contrast was
relatively low.
I would expect that using similar technology, or a flat-bed scanner on rock
slabs or large thin sections would be equally effective for modal analysis.
A digital image of microscope views of thin sections would be equivalent.
The trick would be to ensure a sufficiently high resolution scan (ie
600dpi+) and good colour depth, as would be achieved with a jpeg file set
for 24 or 36 bit colour depth. Most image analysis software should be able
to discern reasonable variations in the colour spectrum from such images. I
would expect that variations in the colour spectrum of altered samples would
be much better done by computer than the human eye.
I'll try to find out details of the software they were using and let you
know later.
cheers,
Brian Grant
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PO Box 8076
Victoria, BC, V8W 3R7
E-mail: [log in to unmask]
Website: http://sites.netscape.net/geomanual/
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----Original Message Follows----
From: "Robert Willan" <[log in to unmask]>
Reply-To: [log in to unmask]
To: <[log in to unmask]>
Subject: Thin sections - modes, grain size analysis
Date: Tue, 11 Jul 2000 19:47:42 +0100
Dear All,
Has anyone used image-analysis techniques to acquire mineral modes, say of
igneous rocks? Is it reliable? I have heard that if the rocks are simple,
it's as quick to do by eye. But if they are altered (yummy!) the human eye
and brain are more reliable.
Secondly - grain-size analysis. I have heard of people scanning a section,
and then using a PC to do the analysis by enhancing grain boundaries and
then using grain centres. What sort of methods are available and who are
the suppliers of any software required?
Many thanks for any advice.
Rob Willan
----------------------------------------------
Dr Robert CR Willan,
Magmatic-Hydrothermal Processes
Geological Sciences Division,
British Antarctic Survey,
Cambridge CB3 0ET, UK
Tel: 01223 221420
FAX: 01223 362616
Email: [log in to unmask]
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